Novel methods envisaged for the elaboration of biologically active alkloids are described which rely upon intramolecular 1, 3-dipolar cycloaddition reactions of nitrile and azomethine ylids with appropriately situated olefins. Immediate synthetic targets include (a) the Amarylidaceae alkaloid pretazettine which has shown marked activity against Ehrlich ascites carcinoma in mice, (b) the convulsive alkaloid dendrobine present in the Chinese tonic Chin Shih Hu, (c) the paralytic agent erythramine, and (d) the Pyrrolizidine alkaloid heliotridine. Moreover, extention of this methodology to the appropriate substrate should facilitate an expedient synthesis of the neurotoxis Physostigmine alkaloid eserethole.